fluidsynth: add module

Fluidsynth is a real-time MIDI synthesizer based on the SoundFont 2
format.

PR #1326

.github/CODEOWNERS

@@ -113,6 +113,8 @@
 
 /modules/services/flameshot.nix                       @moredhel
 
+/modules/services/fluidsynth.nix                      @Valodim
+
 /modules/services/gnome-keyring.nix                   @rycee
 
 /modules/services/gpg-agent.nix                       @rycee

modules/misc/news.nix

@@ -1568,6 +1568,14 @@ in
           A new module is available: 'programs.powerline-go'
         '';
       }
+
+      {
+        time = "2020-06-14T13:30:19+00:00";
+        condition = hostPlatform.isLinux;
+        message = ''
+          A new module is available: 'service.fluidsynth'
+        '';
+      }
     ];
   };
 }

modules/modules.nix

@@ -129,6 +129,7 @@ let
     (loadModule ./services/dwm-status.nix { condition = hostPlatform.isLinux; })
     (loadModule ./services/emacs.nix { condition = hostPlatform.isLinux; })
     (loadModule ./services/flameshot.nix { })
+    (loadModule ./services/fluidsynth.nix { condition = hostPlatform.isLinux; })
     (loadModule ./services/getmail.nix { condition = hostPlatform.isLinux; })
     (loadModule ./services/gnome-keyring.nix { })
     (loadModule ./services/gpg-agent.nix { })

modules/services/fluidsynth.nix

@@ -0,0 +1,57 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.services.fluidsynth;
+
+in {
+  meta.maintainers = [ maintainers.valodim ];
+
+  options = {
+    services.fluidsynth = {
+      enable = mkEnableOption "fluidsynth, the music player daemon";
+
+      soundFont = mkOption {
+        type = types.path;
+        default = "${pkgs.soundfont-fluid}/share/soundfonts/FluidR3_GM2-2.sf2";
+        description = ''
+          The soundfont file to use, in SoundFont 2 format.
+        '';
+      };
+
+      extraOptions = mkOption {
+        type = types.listOf types.str;
+        default = [ ];
+        example = [ "--sample-rate 96000" ];
+        description = ''
+          Extra arguments, added verbatim to the fluidsynth command. See
+          <citerefentry>
+            <refentrytitle>fluidsynth.conf</refentrytitle>
+            <manvolnum>1</manvolnum>
+          </citerefentry>.
+        '';
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.user.services.fluidsynth = {
+      Unit = {
+        Description = "FluidSynth Daemon";
+        Documentation = "man:fluidsynth(1)";
+        BindsTo = [ "pulseaudio.service" ];
+        After = [ "pulseaudio.service" ];
+      };
+
+      Install = { WantedBy = [ "default.target" ]; };
+
+      Service = {
+        ExecStart = "${pkgs.fluidsynth}/bin/fluidsynth -a pulseaudio -si ${
+            lib.concatStringsSep " " cfg.extraOptions
+          } ${cfg.soundFont}";
+      };
+    };
+  };
+}

tests/default.nix

@@ -80,6 +80,7 @@ import nmt {
     ./modules/programs/rofi
     ./modules/services/polybar
     ./modules/services/sxhkd
+    ./modules/services/fluidsynth
     ./modules/services/window-managers/i3
     ./modules/systemd
     ./modules/targets

tests/modules/services/fluidsynth/default.nix

@@ -0,0 +1 @@
+{ fluidsynth = import ./service.nix; }

tests/modules/services/fluidsynth/service.nix

@@ -0,0 +1,24 @@
+{ config, pkgs, ... }: {
+  config = {
+    services.fluidsynth.enable = true;
+    services.fluidsynth.soundFont = "/path/to/soundFont";
+    services.fluidsynth.extraOptions = [ "--sample-rate 96000" ];
+
+    nixpkgs.overlays = [
+      (self: super: {
+        fluidsynth = pkgs.writeScriptBin "dummy-fluidsynth" "" // {
+          outPath = "@fluidsynth@";
+        };
+      })
+    ];
+
+    nmt.script = ''
+      serviceFile=home-files/.config/systemd/user/fluidsynth.service
+
+      assertFileExists $serviceFile
+
+      assertFileContains $serviceFile \
+        'ExecStart=@fluidsynth@/bin/fluidsynth -a pulseaudio -si --sample-rate 96000 /path/to/soundFont'
+    '';
+  };
+}